1. Field of the Invention
This invention relates to closures, and more particularly to a container closure.
2. Prior Art
One and two piece container closures having a base portion with a top surface and a depending skirt for assembly onto the container with a second piece or portion adapted to close an orifice in the base are known to the art. Recently it has been proposed to form such devices of one piece with a hinge connection between the base portion and a top portion, the top portion having a stopper for insertion into the orifice in the base portion (see for example, U.S. Pat. No. 4,047,495). In some such constructions the top portion is movable about the hinge connection with the base portion from an orifice closed position substantially atop the base portion to an orifice open position at an angle to the base portion. Additionally, means have been provided to maintain the top in the open position, such means being generally characterized as an over-center type connection between the top and the base.
In one specific prior art construction the top is attached to the base at two hinged spaced connections at the periphery of the top and base. A flap formed partially from the peripheral side wall of the base and partially from a central land of the top is hingedly affixed at both the side wall of the base and at the central portion of the top. This substantially right angle member forms an over-center type spring connection such that when the top is in the orifice closed position lying atop the base the over-center member will be in a natural substantially right angled position with one leg lying along the periphery of the base and top and the other leg extending inwardly of the top. As the top is opened from a point on the closure opposite the two spaced hinges, the legs of the over-center member will spread apart until the top reaches a substantially right angle position with respect to the base. Thereafter the resiliency of the substantially right angled over-center member will cause the legs to freely assume the prior right angle relation with the one leg extending radially outwardly from the base. This will maintain the cap in an open position at an angle of greater than 90.degree. to the top of the base.
While such prior art devices generally fulfill the requirement of an easily openable closure while maintaining the closure pieces affixed to one another and while maintaining the open top in an open position allowing free dispensing of the ingredients of the container, they require an expensive and complex mold for their formation out of plastic materials. Additionally, because the hinges are positioned at the periphery of the cap, and project beyond the periphery, automatic cap screw-on machines can strip the hinges. When this occurs the over-center feature will no longer work as desired.
It would therefore be an advance in the art to provide a closure cap having a base portion for a fixture to the container and a top portion movable between a position closing an orifice in the base and a position opening in the orifice in the base, with the top portion being connected to the base and with means to maintain the top portion in the orifice open position.
It would be a further advance in the art if such a closure could be provided which is capable of being inexpensively mold formed with minimal material waste.